Power pump



Aug. 29, 1933. R. L. BACHER 1,924,829

POWER PUMP Filed'Jan. 10, 1930 2 Sheets-Sheet l 9, 1933. R, L. BACHER 1,924,829

POWER PUMP Filed Jan. 10, 1930 2 Sheets-Sheet 2 Patented Aug. 29, 1933 POWER PUMP Rollin L. Bacher, Lakewood, Ohio, assignor to The United States Air Compressor Company, Cleveland, Ohio, a corporation of Ohio Application January 10, 1930. Serial No. 419,781

4 Claims.

This invention relates to power actuated grease pumps, such as are used for lubricating various parts of motor vehicles. One form of such pump is illustrated in my Patent No. l,88 -l,507, issued 5 October 25th, 1932. Briefly, such device coniprises a carriage having a grease tank and an electric motor mounted thereon, together with a booster grease pump and an air compressor which are actuated by the motor. The air compressor places an initial pressure upon the grease in the tank, while the booster pump raises the pressure to that required for forcing the grease into the bearings. The grease and air pumps comprise pistons which are arranged in tandem relationship with an eccentric operating directly from the armature shaft to force the pistons in one direction while a spring urges them in the opposite direction. Furthermore, grease is led from the tank into the pump cylinder through a flash port,

which is alternately opened and closed by the piston during the operation thereof.

I have found in practice that the use of a spring above the piston is impractical, as a large compression space is required to obtain sufficient force to return the pistons. Such large space resulted in the occurrance of air pockets within the pump and prevented the building up of the desired pressure.

I have also found that all grease contains impurities, such as relatively small solid particles and abrasives, which pass through the strainer and are caught by the piston on its upward stroke and sheared off, thereby causing rapid wear on the side of the piston and also on the side of the cylinder. As the pump necessarily has a very short stroke, due to the high speed at which it operates, it has been found that these parts would wear within thirty to ninety days to such extent that the necessary pressure could not be maintained. Furthermore, particles of foreign matter would lodge in the discharge valve and prevent the building up of pressure in the discharge conduit.

To assist in placing initial pressure upon the grease in the container, a follower plate has been placed on top of the grease. The air which forms the initial pressure in the tank acts directly on top of the follower to force it downwardly. Aocordingly, when the greaseis used up, the follower O is at the bottom, and in many instances, it has been found that the operator has placed a new charge of grease in the container without previously having removed the follower plate.

A further operating problem which has become apparent is the fact that foreign particles in the grease lodge between the outlet valves and its seat, so that no pressure can be built win the dis charge conduit. This difficulty arose notwithstanding the fact that a fine mesh wire screen was used at the bottom of the container to strain 69 the grease.

The objects of the present invention therefore, are to provide a construction which will prevent the formation of air pockets within the grease pipe, which will prevent the objectionable wear on the piston and cylinder walls due to impuri ties in the grease, which will practically eliminate the possibility of failure of pressure in the discharge conduit due to foreign matter lodging in the discharge conduit, and which will minimize 70 the possibility of recharging the tank without having previously removed the follower plate.

The preferred manner of carrying out these ob jects is illustrated in the drawings, wherein Fig.

l is a side elevation partly in section of a device embodying my invention; Figs. 2 and 3 are sections taken on planes indicated by the correspond ingly numbered lines in Fig. 1.

A grease pump embodying my invention is shown in the drawings as comprising a Wheeled 8o carriage 10, which supports an electric motor 11 and a grease reservoir or tank 12. The reservoir is preferably supported above the electric motor by a saddle 13, which is fastened to the carriage by bolts 14. A member 9 rests upon the saddle S5 and forms a bottom for the reservoir while a lid 15 is disposed at the top and is removable to permit the insertion of the desired material. A bolt 16 is shown as beingin threaded engagement with a central opening in the saddle and as projecting beyond the lid. Such projecting portion is threaded and is adapted to receive a nut 17 which functions to clamp the various parts of the reservoir to the saddle. A cross bar l8 may extend through the nut and be used for enabling 9 the reservoir parts to be clamped together in an expeditious manner. The various interfitting joints of the reservoir and also the connection between the nut and the lid are made air-tight.

Within the reservoir, a followerplate l9 rests 190 upon the top of the lubricant and acts as a piston to force the material into the booster pump. A strainer 20 is preferably used within the reservoir and above the discharge passageway 21, which leads from the bottom of the reservoir beneath the strainer.

To prevent the refilling of the reservoir without first removing the follower plate, I provide a sleeve 22, which is slidably mounted upon the bolt 16. The sleeve carries a plate 23 at the upper end thereof and has a shoulder 24 at the lower end thereof. The follower plate 19 is in turn slidably mounted upon the sleeve 22 between the plate and the shoulder. Thus, it is evident that in order to recharge the reservoir, the plate 23 must first be lifted and that in doing so, the sleeve will be raised until the shoulder engages the follower plate. Continued lifting of the plate will raise the follower.

The material fl wing from the reservoir is led into a booster pump and then is forced into a discharge conduit. In the improved construction, such booster pump comprises a cylinder block 25, which is formed at its lower end to make a cylinder 26 and at its upper end a cylinder 27. The cylinder block is shown, as being fastened to'a base 28 by securing members 29, while the base in turn is illustrated as being attached to the wheeled carriage by bolts 36. To reciprocate the piston and plunger within the cylinder block, I have shown the motor, as having the armature shaft 37 thereof, extending into the base 28 and as being provided at the end thereof with an eccentric 36, which is operatively connected by a connecting rod 34 to the piston 33. Thus, the pistons are directly and positively connected to the motor.

To prevent wear on the pistons and cylinder incident to the shearing of impurities between the piston and cylinder, I place the inlet conduit beyond the extreme end of the forward stroke of the piston. A valve 38 is disposed in this inlet conduit, as is shown particularly in Figs. 2 and 3. In this way, a full cylinder charge is obtained on each stroke of the piston.

For the purpose of minimizing the possibility of foreign matter lodging in the dis harge passageway, I provide two separate discharge valves 39 and lo respectively. These valves are placed in tandem relationship in the discharge passageway 4l,.which communicates with a discharge conduit 42.

To safeguard against building up an excessive lubricant pressure, I have shown a by-pass valve 43 which leads from the discharge passageway and which is normally maintained closed by a spring 44. The tension on such spring may be set to permit opening of the valve at a predetermined pressure by adjustment of a set screw 45. A by-pass conduit 46 leads from the by-pass valve into the inlet passageway 21. Thus, if the lubricant pressure in the discharge conduit exceeds a predetermined amount, the by-pass valve will open andiallow the lubricant to flow back into the container until the pressure conditions are again restored to normal.

To remove any air which may be carried into the booster pumpcylinder with the grease, and

To maintain pressure within the tank above the follower, I utilize the piston 33 and its associated c linder as an air compressor. The inlet to the pump is through a valve 48 while the discharge therefrom, is through a valve 49 which communicates with a conduit 50. This is shown as extending upwardly into the tank adjacent the wall 12 and through openings in the follower plate and closure plate. In this way, air is conducted to the upper part of the tank and pressure is placed upon the grease therein. Suiiicient clearance is maintained between the top of the piston and its associated cylinder to prevent the building up of excessive air pressure within the tank.

From the foregoing description, it will be apparent, that I provide a simple and efficient means for eliminating the operating difficulties which have been encountered in a grease pump of this form.

I claim:

1. In combination, a grease tank, a follower plate movable vertically therein adapted to rest upon the grease within tank, a guide member extending vertically through the tank and adjacent the midportion thereof, the follower plate being slidably mounted along said member, the member having a shoulder adjacent the bottom thereof for engaging the underside of the follower and there being a plate mounted rigidly on the member adjacent the top thereof, said plate functioning to prevent refilling of the tank until the follower is removed.

2. In combination, a grease tank, a follower plate movable axially within the tank and adapt- T said tank, means for guiding said follower for sliding movement axially of said tank, a plate extending transversely of said tank at one end tank for lubricant, a follower adapted to upon the lubricant in thereof, said plate normally forming substanopening through which the tank is filled with grease and means extending between the member and plate for raising the member, the member being held normally in relatively stationary position and operating to prevent refilling of the tank until it is raised with reference thereto.

ROLLIN L. BACHER. 

